The present invention relates in general to data processing systems, and in particular, to graphics rendering in a data processing system.
Sophisticated graphics applications in modern data processing systems require the graphics data processing hardware to generate larger and more complex images. For example, virtual reality applications may display a panoramic view of a scene, requiring a display of a plurality of component images to form a composite image. Each image in the composite may, itself, be complex, requiring a dedicated processor to compute the component image. The composite may then be generated by providing each of the component images to an end station processor that generates a composite therefrom. Dedicating a data processing system to generate the composite also adds cost to the overall system. Additionally, the display of the scene may require multiple display devices, driven by a display driver associated with the processor generating the composite image to be displayed on the corresponding display device. This increases the cost of the system even further. Thus, there is a need in the art for a mechanism to combine graphics data streams to form a composite graphics signal to be provided to a display device and that may be incorporated in a data processing system economically and with a reduced development schedule.
The aforementioned need is addressed by the present invention. Accordingly, there is provided, in a first form, an apparatus for merging pixel data. The apparatus includes a buffer operable for receiving pixel data from a first source, and first selection circuitry operable for receiving pixel data from the buffer and pixel data from a second source. The selection circuitry selects for outputting the pixel data from the buffer and pixel data received from the second source, and the selection circuitry is operable for outputting the pixel data to a display device. The buffer outputs the pixel data in response to a first clock signal.
There is also provided, in a second form, a method of merging pixel data. The method receives pixel data from first and second sources and loads the pixel data from the second source in a buffer. The method further selects for outputting, in response to a dynamic switch signal, the pixel data from the first source and the pixel data stored in the buffer. The buffer outputs the stored pixel data in response to a first clock signal from the second source.
There is also provided, in a third form, a data processing system. The data processing system includes a central processing unit (CPU) and a graphics system operable for receiving graphics data signals and control signals from the CPU. The graphics system includes a buffer operable for receiving pixel data from a first graphics engine. The graphics system also includes a second graphics engine operable for generating pixel data in response to the graphics data signals and first selection circuitry operable for receiving pixel data from the buffer and the pixel data from the second graphics engine, wherein the selection circuitry selects for outputting the pixel data from the buffer and pixel data received from the second graphics engine, the selection circuitry being operable for outputting the pixel data to a display device, and wherein the buffer outputs the pixel data in response to a first clock signal from the second graphics engine.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention.